1. 24: rats were infected with 5,000 N. brasiliensis larvae and were examined hourly from 12 to 24 hours after infection for larvae in the blood and the lymph nodes.

2. Larvae were found in small numbers in the blood and the lymph nodes; the maximum number of positive blood samples occurring sooner after infection than the maximum number of positive lymph nodes.

3. These results were discussed particularly in relation to the timing of the skin to lung migration, and it was concluded that the larvae of N. brasiliensis migrate mainly in the blood but also in the lymph.

The schistosome transmitting molluscs, Physopsis africana and Biomphalaria tanganikanus, from the Belgian Congo, carried the metacercaria of Echinoparyphium recurvatum and of Echinostoma revolutum, which have been recorded for the first time from the Southern half of the African Continent. Further research may indicate their wider distribution in this Continent.

Development of the larval stages and heavy encystment of the metacercaria of these echinostomes in the schistosome transmitting molluscs led to death of the snails. The use of other trematode species, particularly echinostomes may offer great prospects in the field control of schistosome transmitting molluscs.

A technique is described for the recovery of strongyloid infective larvae from a large number of separate small sample units of pasture. The larvae recovered from each sample unit can readily be counted individually. Tests of the technique have shown that it will recover approximately 90% of the larvae present. The efficiency of the technique is independent of the number of larvae present and of the quantity of sediment containing infective larvae which is obtained from washings of pasture samples.

The life-cycle of many strigeoid trematodes contains encysted metacercariae as disseminating and infective stages. The cyst wall may vary in form from a thin bag-like structure loosely covering the metacercaria (as in Posthodiplostonmm) to a thick layer, closely investing the parasite and forming a cyst of fixed outline. The cyst wall enclosing the metacercaria of Cyathocotyle is of this thick, rigid type. Extensive histochemical studies have been carried out on the cyst wall of Posthodiplostonmm (Hunter and Hunter, 1940; Bogitsh, 19G2), but the characteristics of the other types of strigeid cyst wall are as yet undefined.

A large number of cestodes from the intestines of sheep and goats were collected from the slaughter houses in and around Lyallpur city of West Pakistan in the begining of 1965 and preserved in separate containers in connection with some other work. On examination of the collection made from goats, a specimen was found which had the characteristics of genus Moniezia but was not referable to the species so far described. On further examination two complete specimens were isolated from the collection and stained after fixation under moderate pressure.

1. The morphology of the infective larvae of Cardiofilaria nilesi and Pelecitus sp. in Mansonia crassipes is described in some detail, and sex differences have been noted in them.

2. Infective larvae of C. nilesi can be distinguished from those of Wuchereria bancrofti by the form of the caudal papillae.

3. A brief description is given of four unidentified larvae from other wild-caught mosquitoes in Ceylon.

Brood capsules having scolices on their outer wall were observed many times in hydatid cysts of buffaloes from India.

As a result of their feeding habits, birds of 36 or more families have proved to be susceptible to a large number of dicrocoeliine trematodes living principally in the bile ducts and gall-bladder of their hosts (Faust, 1966). As more species of avian hosts are examined and their liver flukes studied, additional species are described and previously recognized species are reported from new hosts and new geographical areas (Lumsden and Zischke, 1963).

In 1958, Yamaguti differentiated Dicrocoeliinae Looss, 1899 into 8 tribes, one of which he named Lutztrematini, having as cardinal characters an acetabulum much larger than oral sucker and testes tandem or diagonal; single genus Lutztrema Travassos, 1941 and L. obliquum (Travassos, 1917) as type species. The avian dicrocoeliine species described in this communication has important morphological characters agreeing with the Lutztrematini and others lacking agreement. In consequence, it has seemed necessary to create a new genus, Paralutztrema, related to, but generically separate from Lutztrema.

The indigenous dogs of Malawi form a fairly homogeneous group. The general type is a smooth-haired, medium-sized, terrier dog in many ways not unlike the Basenji of the Belgian Congo. Consequently it may be assumed that the local breed of dog has, generally speaking, had very little contact with exotic breeds and that it is quite possible the parasitic populations which it supports are also truly indigenous. A unique opportunity of exploring this unknown terrain presented itself when, as a result of an outbreak of rabies, it was decided to thin out the unvaccinated dog population as a veterinary control measure.

1. Three hundred and eighty three birds belonging to fifteen species found dead from starvation as a result of a severe cold spell on the island of Skomer, between 2nd and 5th January 19G2, were examined for enteric helminths. The age, sex and weight of each bird was determined whenever possible and on dissection, the species, location and number of helminths was recorded.

2. Seventeen species of helminths were found, providing sixteen new host records and five new British records.

3. In general, changes in the mean number of helminth species and specimens per bird and per infested bird is directly correlated with changes in the percentage incidence of infestation.

The paper discusses the occurrence of nematodes of the genus Rhabditis in man and reports the finding of specimens of what appears to be Rhabditis (Rhabditella) axei in the urine of an African female in Rhodesia. A discussion is included on the possible method of infection.

Echinonema cinctum is redescribed and referred to the Superfamily Seuratoidea: Seuratinema brevicaudatum is redescribed and the genus Seuratinema is provisionally accepted.

2. The structure of the head in several species of the Seuratoidea is described and it is shown that the mouth opening is bilaterally symmetrical in Seuratinema and Seuratum.

3. After a discussion on the developmental origins of the nematode head it is pointed out that all the labial structures in the Camallanidae and the Spiruroidea arise from a region of secondary elongation, i.e. from a cheilostome, while the paired jaws in the Cucullanidae arise as a modification of the oesophagus, i.e. are an oesophastome. As a consequence the family Cucullanidae is referred to the Seuratoidea : Ascaridida while the Camallanidae are left in the Spirurida.

Two experiments were undertaken to assess the role of the mouse in the life-cycle of Aelurostrongyhis abslrusus. In the first, 18 mice were fed first stage larvae and killed one month later. At post-mortem and histopathological examinations larvae were not demonstrated and attempts to extract larvae from a proportion of the mice were also negative. In the second experiment, 24 mice were fed heavy doses of first stage larvae. Subsequent examinations failed to reveal the presence of larvae and post-mortem and histopathological examinations performed on two cats, each of which had been fed with six of the mice, failed to reveal the presence of lungworms. It is concluded that mice do not act as intermediate host for Aelurostrongyhis abstrusus.

Microfilariae were demonstrated in stained blood films from two New Guinea frogs, Cornufer papuensis, and this material was later given to me by a colleague. The frogs, which had been preserved in alcohol for some months, were examined for adult forms after having been softened in a solution of equal parts of glycerol and 70%alcohol. One male, one female and the anterior part of a second female of a new species of the genus Icosiella Seurat, 1917 were found in one frog. Two females and four males of a new species of the genus Ochoterenella Caballero, 1944 were found in the second frog.

By means of egg counts, faecal cultures and post-mortem examinations of sheep the course of an infestation of Ostertagia circumcincta was followed from March until the following January in a flock of 100 twelve-months-old wethers at Wellington, N.S.W. The highest adult infestations and egg counts occurred in March and January, while during the winter months there was a continual accumulation of inhibited fourth stage larvae in the abomasal mucosa. The data suggest that the adult population observed in January arose from the inhibited population observed during the previous winter and that one of the factors controlling the development of the inhibited population was larval intake.

The Sheathbill is a distinctive bird breeding on the islands of the Scotia Arc and the Graham Land peninsula, and regularly occurring north to the Falkland Islands, the Magellanic Islands and the Atlantic coast of Argentina (Jones, 1963). Rather surprisingly no cestodes have previously been recorded or described from this bird.

The following account describes Nototaenia fileri gen. et sp. nov. and Lateriporus ausiralis n.sp. from two of 13 adult Sheathbills collected on Signy Island in July and October 1965 by Mr Charles Howie of the British Antarctic Survey, preserved in deep-freeze, and later entrusted to us for examination.

Attempts were made to induce increased resistance to caecal worm infections in chickens and turkeys by giving 5-week-old birds embryonated Heterakis eggs. To test for such resistance, the birds were challenged 28 days later by feeding comparable numbers of embryonated eggs. To study the possible influence of any response on the transmission of blackhead, some of the birds received Heterakis eggs from worms grown in birds that had blackhead.

In blackhead-free chickens there was only a slight reduction in the number of worms recoveied from the initial infection as a result of the superimposed second infection. However, there were 37% fewer worms from the second feeding of eggs than were present in the control birds that had had no previous Heterakis infection. In blackhead-free turkeys, the immunized birds had fewer worms from both doses than did the controls. These reductions averaged about 40% in both instances.

After five to six weeks, and for a varying period thereafter, cats infested with Aelurostrongylus abstrusus evacuate first stage larvae in their faeces. Hobmaier and Hobmaier (1935), Blaisdell (1952) and MacKerras (1957) collected larvae for eight weeks, two years and seven months, respectively, after patency. Cameron (1927) found that larvae, extracted from faeces, lived for 11 days but were killed by freezing. Since the fate of such larvae is of importance with regard to the incidence of lungworm disease in the cat and because of the divergence of opinion concerning the viability of first stage larvae, it was considered necessary to establish the life-span of such larvae under various controlled conditions.

It has been suggested (Hammond, 1967) that Acanthocephalus ranae absorbs a large proportion of its nutrients through the surface of the trunk, while lipids may be excreted through the surface of the proboscis. The performance of these functions by the proboscis and trunk may well be affected by the mode of attachment of the parasite, and by its behaviour within the host.

The working of the proboscis apparatus of Acanthocephalus ranae has been described (Hammond, 1966a), but its operation in attaching parasite to host has been outlined only briefly (Hammond, 1965).

Twenty-eight adult specimens of 2 new species, Aphelcnchoides appendurus and A. montanus, were collected from the rhizoids of moss adhering to the bark of pine trees in the Mussoorie Hills, at an altitude of 7,500 feet above sea level, in Uttar Pradesh, India.

The 2 new species, which belong to the “parietinus” group of the genus Aphelenchoides Fischer, 1894, are described and illustrated.